Of 201 

Dopy 1 



The Effect of the Age of Sire 

and Dam on Offspring 

in Dairy Cows 



C. L. ALLEN 



Reprinted wilhoul change oj paging, from the 
Journal of Heredity (Organ of the American 
Genetic Association), Vol. XIII, No. 4; Wash- 
ington, D. C, April. 1922. 



THE EFFECT OF THE AGE OF SIRE 

AND DAM ON THE QUALITY OF 

OFFSPRING IN DAIRY COWS 



A THESIS 

PRESENTED TO THE FACULTY OF THE GRADUATE SCHOOL 
OF CORNELL UNIVERSITY IN PARTIAL FULFILLMENT 
OF THE REQUIREMENTS FOR THE DEGREE OF 

DOCTOR OF PHILOSOPHY 



BY 

CHARLES LORING ALLEN 



920 



Reprinted from The Journai. of Heredity (Organ of the American Genetic 
Association), Vol. XIII, No. 4 ; Washington, D. C, April, 1922. 



Reprinted, leithou! cinuu/c of piujing. from the Journal of Heredity (Oraan of the Aineriean 
Ci'e)ietie .Issoeiation J , J'ol. XIII, Xo. i ; IVashinoton. P. C. .Ipril, iqjj 



THE EFFECT OF THE AGE OF 

SIRE AND DAM ON THE 

QUALITY OF OFFSPRING 

IN DAIRY COWS 



C. L. Allex 

Cornell University, Ithaca, N. Y 




A FAMOUS HOLSTEIN SIRE 

Figure 10. Ormsby Kornclyke Lad (102469) one of the great sires of the Holstein Friesian 
Breed. His daughters are noted for their high production records for both 7 day and yearly work. 
He has 18 daughters with records of over 30 pounds of butter (80% fat) in 7 days. He also has 
14 daughters with records of over 1000 pounds of butter (80% fat) in one year. The sire of Ormsby 
Korndyke Lad was only 23 months of age when he was born and his dam was just a little over 4 
years of age (51 months). Photograph from Holstein Friesian World. 



THE effect of the age of parents on 
the quahty of the offspring is in a 
large measure concerned with the 
idea of cumulative inheritance, par- 
ticularly if we do not consider the 
matter of the proven sire or dam. 
If an animal is a more valuable 
parent after it has attained maturity, 
it is more valuable for one of two rea- 
sons. Either the mature animal must 
be able, merely because of its full 
physical development better to im- 



167 



press its characters on its offspring, or 
the mature animal must in the process 
of attaining maturity, ha\'e become 
endowed with something, due to train- 
ing or environment, which it can trans- 
mit to its progeny. After a century of 
study, this matter is far from settled 
and the question as to the possible 
effect of environment on the transmis- 
sion of a tendency to increase or de- 
crease certain quantitative functions 
is still important. 



i68 



The [ournal oi Hereclitv 




JOHANNA DE KOL CONCORDIA 

Figure 11. At three and a half years of age her record was 19037 pounds of milk and 671 
pounds ot butterfat. Her sire, Sir Clothilde Concordia, was two years nine months of age when 
she was born, while her dam, Cold Spring Johanna De Kol 2nd, was three years and a half old. 
The great number of cases where the parents of high producing cows are as young, or younger 
than these, leaves no doubt that the off-spring of immature parents are just as good producers or 
transmitters of production as those born when the same parents are mature. Photo by U. S. 
Department of Agriculture. (See text, p. 173.) 



In practical breeding, it would be 
very advantageous to know definitely 
whether the young born of immature 
parents are as ^'aluable for production, 
and for reproducing their kind, as 
those born of more mature parents. 
It is the aim of this paper to show 
whether the parentage of a group of 
high producing or superior cows aver- 
ages older than the parentage of a group 
of comparatively low producing or 
inferior cows. The paper also attempts 
to show the percentage distribution of 
offspring for the various ages of both 
sire and dam; the age when cows 
actually make their best records; and 
whether the offspring of very young or 
very old animals are inferior. 



METHOD 

The data reported in this paper were 
taken from Volume 27 of the Ad- 
vanced Registry Year book and the 
Herd Books of the Holstein Friesian 
Association of America. 

The superior class of animals chosen 
include those that up to April 30th, 
1916, had made records of 24 pounds 
or more of butterfat in seven days. 
This included all of the so-called 
thirty pound cows since 24 pounds of 
l)utterfat is equal to 30 pounds of 
eighty percent butter. For purposes 
of more careful study, this class was 
divided into three groups as follows: 

Group I — All cows producing over 
27.3 pounds of butterfat in 7 days. 



Allen: Effect of Parents' Age on Quality of Dairy Cows 169 



Group II — ^AU rows producing be- 
tween 25.6 and 27. v^ pounds of liuttcr- 
fat in 7 days. 

Group III — All cows producing be- 
tween 24 . and 25 . 6 pounds of butter- 
fat in 7 days. 

The comparatively inferior class of 
animals chosen includes all of the so- 
called mature cows, that is, cows five 
years of age or o^•er, that produced 
less than fourteen pounds of butter- 
fat in seven da>'s and were entered in 
the 27th Volume of the Holstein Frie- 
sian Advanced Registry Year Book as 
entries or re-entries. This class was 
divided into three groups that were 
fairly comparable in numbers to the 
groups of the superior class, as follows: 

Group I — All cows producing be- 
tween 12 and 12.5 pounds of butter- 
fat in 7 days. 

Group II — All cows producing 
between 12.5 and 13.0 pounds of 
butterfat in 7 days. 

Group III — All cows producing be- 
tween 13.0 and 14.0 pounds of butter- 
fat in 7 days. 

The groups were arranged so that 
the very highest producers were in 
group 1 of the Superior Class and 
the very lowest producers were in 
group 1 of the Inferior Class. Then, 
if there was any difYerence in age, 
it was thought that the first groups 
should be further apart than the second 
and third groups. 

The 7 day record was chosen as the 



number of records were available and 
the 7 da\' record is generally recog- 
nized as a ^■alual)le method of deter- 
mining the i)roducti\'c ability of dairy 
cows. 

Three generation pedigrees were 
compiled for all the cows of both the 
Superior and Inferior Classes. These 
pedigrees included the date of birth 
for all animals in e\'ery pedigree. This 
makes it possible to compute the dif- 
ference in age between any animal and 
its parents and tells us the age of the 
parents at the time the animal in 
question was born. This also provides 
data for determining the average differ- 
ence in age between generations, and 
allows the calculation of the percentage 
distribution of offspring according to 
the age of parents, making it possible 
to observe whether more good cows 
or poor cows are born from very young 
or very old dams. The difTerence in 
age between parent and offspring was 
computed in months to the nearest 
month. 

In order to determine at what age 
the superior cows made their records, 
it was necessary to take this data 
directly from the Advanced Registry 
Year book and record it on the pedi- 
gree. 

RESULTS — THE DIFFERENCE IN AGE 
COMPARED 

Table I gives the average age of the 
ancestry of the Superior and the Infer- 
ior Classes by groups and for the classes 



basis for this study because a larger 

Table I. Average Age, in Months, of Ancestry of Superior and of Inferior Classes of Cows 





Superior Cows 




Infe 


rior Cows 






Ancestor 


Group 1 


Group 2 


Group 3 


Class 


Group 1 


Group 2 


Group 3 


Class 


Sire 


44.3 
62.8 


51.7 
63.6 


46.3 
61.2 


47 
61 


1 + 
9 + 


647 
890 


45.7 
60.0 


44.6 
62.2 


41.6 
64.7 


43 
63 


1 + 
1 + 


S?9 


Dam 


.941 


Paternal grand sire. 


48.6 


49.6 


49.6 


49 


5 + 


717 


45.4 


46.4 


46.7 


46 


6 + 


646 


Paternal grand dam. 


64.9 


65.2 


67.6 


66 


7 + 


929 


66.5 


69.4 


65.8 


66 


7 + 1 


034 


Maternal grand sire. 


42.3 


41.4 


42.3 


42 


1 + 


507 


44.8 


43.0 


43.4 


43 


6 + 


508 


Maternal grand dam 


65.2 


63.0 


59.6 


61 


+ 


873 


65.0 


69.4 


62.8 


64 


7 + 1 


013 


Great grand sire' . . . 


44.3 


44.8 


48.1 


46 


9 + 


640 


45.4 


47.9 


43.8 


45 


1 + 


602 


Great grand dam' . . 


61.3 


59.0 


63.8 


62 


5 + 


939 


61.7 


72.1 


64.7 


65 


7 + 1 


006 


Number of pedigrees 


























in each group and 


























class 


86 


121 


404 




611 




111 


114 


285 




510 





' Great grand sire refers to sire of paternal grand sire. Great grand dam refers to the dam of 
the maternal grand dam. 



170 



The Journal of Heredity 



as a whole. This table allows us to 
make comparisons and determine any 
significant difference between the aver- 
age age of the superior cows and the 
(comparatively) inferior cows. 

It win be noted in table I that 
the greatest difference in age is four 
months and that this occurs in the 
case of the sires. This difference 
might seem to be somewhat significant 
in the light of the probable error as a 
measure of its probable significance. 
The difference is more than three 
times the probable error but the prob- 
able error in this case is small. We 
must remember, however, that four 
months is not a very marked difference 
and this difference loses a large part of 
its significance when we study the 
group averages. There is more differ- 
ence between the groups within the 
classes even here than there is between 
the classes themselves. This is still 
more noticeable in other places in the 
table where the class difference is not 
so great. Take for example, the case 
of the dams, the great granddams, or 
the maternal grand sire. In each of 
these cases, the difference is probably 
insignificant in the light of the prob- 
able error, and in each case, the differ- 
ence between the groups within the 
class is greater than the difference 
between the classes. 

The real difference in age between 
the various parents and generations is 
more clearly shown by means of a 
pedigree. Such a pedigree is given in 
Figure 12. 

It is evident that there can be no 
increased hereditary value due to the 
age of the dams, for in every case ex- 
cept one, the dams of the Inferior Class 
average older, though not significantly 
so, than the dams of the Superior Class. 
In the one case, that of the paternal 
granddam, they average exactly alike. 

From a study of Table I and the 
pedigree. Figure 12, it is apparent 
that there is no significant difference 
between the ages of parents of the 
Inferior and of the Superior Classes. 
In only one case is the difference out- 
side the limits defined by three times 
the probable error. In this case, the 



small difference between the class 
averages can hardly be considered sig- 
nificant when there is so great a differ- 
ence between the group averages within 
the class. ♦ 

BULLS ARE NO MORE VALUABLE 
PARENTS AS THEY GROW OLD 

Turning our attention again to the 
pedigree, Figure 12, we note that in 
every case the Superior sires on the top 
line of the pedigree are older than the 
corresponding inferior sires. The dif- 
ference is probably not significant 
even in the case of the sires, but the 
tendency persists. 

This led to a study to determine 
whether a bull produced superior 
offspring as he grew older. From a 
study of four bulls having a total of 
five hundred and six daughters, it 
seems that bulls may or may not have 
better daughters as they grow older, 
depending on the quality of animals to 
which they are bred. As a bull proves 
his superior worth, he is very likely to 
be bred to better cows and produce 
better offspring. This probably ac- 
counts for the difference shown in the 
pedigree. This whole matter will be 
fully discussed in a later paper. Thus 
the difference in age of sires can be 
very readily assigned to the use of the 
sires and there is no indication that 
the sires are any better when they are 
old than when young and immature. 
In fact the frequency distribution, 
Figures 13 and 14, tends to show that 
the young parent of either sex is just as 
valuable as a parent when immature 
as it is in later life. The frequency 
curves include only the sires and dams 
of the first generation. 

FREQUENCY DISTRIBUTION ACCORD- 
ING TO AGE OF SIRE 

In the frequency curves. Figures 
13 and 14, it will be observed that 
the curves run very nearly parallel 
throughout. The curves start high, 
indicating that a large percentage 
of cows in both the Superior and 
Inferior Classes are sired by very 
young bulls. In this connection, it 
will be remembered from Table I that 



Allen: Effect of Parents' x^ge on Quality of Dairy Cows 171 



46.9 

45.1 

Great Grand Sire 



49.5 

46.6 

Grand Sire. 



47.1 
43.1 



Sire 



Grand Dam. 
66.7 

66.7 



42.1 

43.6 

Grand Sire. 



Dam . 



61.9 

63.1 

Grand Dam . 
61.0 

64.7 

Great Grand Dam 
62.5 

65 .7 

AN AGE-PEDIGREE OF THE TWO CLASSES OF COWS 

^"■iGURE 12. This shows the average age of the ancestors of the superior cows (Bold-face type), 
and of the inferior cows (Italics). It is evident that there are no significant differences in the age 
of the forebears of the two classes. (See text, p. 169.) 



the sires of the Superior Class average 
less than four years of age, 46 . 4 months 
to be exact, and that the sires of the 
Inferior Class average somewhat 
younger. The largest number of off- 
spring were born when their sires were 
from two and one-half to three years 
of age. This means that these bulls 
sired a larger percentage of their off- 
spring between twenty-two and twenty- 
seven months of age than at any 
other time. 

Table II shows very clearly just 
how our purebred sires are used. It 
indicates that improvement has been 
based on the selection of young sires 
rather than on the use of tried sires. 

THE PROVEN SIRE 

A bull cannot be called a proven sire 
until his first crop of heifers come in 
milk and can hardly be so called 
until these heifers have milked at 
least one year. Thus a bull can hardly 



be called a proven sire until he is five 
years of age. In general practice, the 
percentage of cows sired by unproven 
bulls is probably much higher than the 
percentage shown for the animals in- 
cluded in this study. This means that 
even the breeders who are making 
records use a tried sire for only a 
small percentage of their cows. That 
the tried sire is more valuable is indi- 
cated by the fact that 21.1 percent of 
the Superior cows are daughters of 
tried sires, whereas only 15.9 percent 
of the Inferior cows are daughters of 
bulls of an equal age. This may seem 
to conflict with the idea that the bull 
when old is not more valuable, but 
the paper referred to above shows that 
he is not more valuable as a parent. 

FREQUENCY DISTRIBUTION ACCORD- 
ING TO AGE OF DAM 

The frequency curve for the dams, 
Figure 13, is very much more irregular 
than the curve for the sires but on the 



172 



The Journal of Heredity 



18. Op 










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SUPERIOR CLASS . 
INFERIOR CLASS 














































































































































































































































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24 30 36 42 48 54 60 66 72 78 



90 96 102 108 114 70 126 132 138 144 150 156 1«.2 



174 180 186 192 198 204 



AGE OF DAMS IN MONTHS 
FREQUENCY CURVE FOR DAMS 

Figure 13. The percentage of young born by dams of various ages is shown in this chart. 
The age of the dams is computed for six-months periods, and the upper age Hmit of these groups 
is shown. That is, all the dams 24 months and under are considered 24 months old, those between 
24 and thirty months of age, as 30 months old, etc. It is evident that much the greater number 
of calves are born by very young cows, the quality of whose offspring cannot be known. (See text, 
p. 171.) 



Allen: Effect of Parents' Age on Quality of Dairy Cows 173 



whole, even here, the 
curves run nearly 
parallel. There is, 
however, a distinctly 
larger percentage of 
high producers born 
of very young dams 
than there is of low 
producers. It is hard 
to account for this 
unless the Superior 
Class have received 
better care and are 
bred younger on the 
average than the In- 
ferior Class. 

It will be noted in 
connection with Table 
III that a slightly 
larger percentage of 
the Superior Class 
were born from dams 
under five years of 
age than there were 
of the Inferior Class. 
In later life, the two 
classes are very near- 
ly alike and almost 
exactly as many of 
the Superior Class 
were born from dams 
over eight years of 
age as were born in 
the Inferior Class 
from dams of a 
like age. The per- 
centage having dams 
over twelve years is 
exactly alike for both 
classes. 

VALUE OF OFFSPRING 

OF VERY YOUNG 

AND VERY OLD 

PARENTS 

From a study of 
the frequency curves 
and Tables II and 
III, it is evident that 
the young bom from 
very young parents or 
from very old parents 
are as valuable as 
any for productive 



IB.O 




1 








































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16.5 








































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C 


IIPFRIOR C.\ A^f^ 
NFERIOR CLASS - 




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1 
1 








1 




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15 


























14.5 


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12 5 


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8.5 
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24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120 126 132 138 144 

AGE OF PAM» IN ^rONTHS 

FREQUENCY CURVE FOR SIRES 

Figure 14. The co-ordinates are the same as in the preceding 
chart. The same conclusions apply even more strikingly in this 
case, as the sires are not used for breeding purposes as long as the 
dams, A sire cannot be considered a proven sire until his first 
crop of daughters have been in milk at least a year, which means 
that he must be five years of age. These figures are for a selected 
class of sires and show that even the breeders who are making 
records use tried sires for only a small percentage of their cows. 
(See text, p. 170.) 



174 



The Journal of Heredity 




WATSON SEGIS PONTIAC HOMESTEAD 

Figure 15. She was born when her dam, Watson Segis Pontiac, was just 2 years, 2 days old, 
when her sire, Piebe Laura AlHe Homestead King, was a senior two-year-old. Her record is 
25,360 pounds of milk and 928 pounds of fat. Her mother has a record of 844 pounds of fat, and 
she is the daughter of King Segis Pontiac Count, a great breeding sire, who was only a little over 
two years old when she was born. Photo by U. S. Department of Agriculture. 

Table H. The Percentage of Daughters Born on or before a Given Age of Sire, and the Age 
of the Sire at the Time the Dams of the Daughters were Bred 



Age of Sire when Daughters 
were born 


Age of Sire when the Dams of 
Daughters were Bred 


Percentage of Daughters 


Superior 


Inferior 


30 Months and Under 
36 Months and Under 
60 Months and Under 
Over 60 Months 


21 Months and Under 
27 Months and Under 
51 Months and Under 
Over 51 Months 


27.5 
45.3 
78.9 
21.1 


28.0 
45.3 
84.1 
15.9 



Table HI. Showing the Percentage of Young Born Before and 


After a Given Age of Dam 


Age of Dam when Daughters 
were born 


Percentage of Superior 
Daughters 


Percentage of Inferior 
Daughters 


30 Months and Under 

36 Months and Under 

60 Months and Under 

Over 8 years 


17.2 
26.2 
57.1 
14.8 
2.8 


13.3 
21.6 
54.9 
15 


Over 12 Years 


2.8 



Allen: Effecf of Parents' Age on Quality of Dairy Cows 175 




^ilf* ■■'~^: 



.*^~--: f 



A SIRE OF RECORD-MAKING DAUGHTERS 

Figure 16. King Hengeveld Aaggie Fayne (56635) has shown remarkable ability to tr<insmit 
production. He was slaughtered when only three years of age and as a result has only 31 A. R. O. 
daughters. Eleven of these daughters have records in e.vcess of 30 pounds of butter (80% fat) 
in 7 days. Four of his daughters have yearly records. Three of these records made by two and 
three year old heifers average 21,762.2 pounds of milk and 978,93 pounds of butterfat. The other 
yearly record was made by a mature daughter and is 15,486.1 pounds of milk and 530.89 pounds 
of butterfat. 

King Hengeveld Aaggie Fayne was born when his parents were quite young. His sire was 
22 months of age and his dam 28 months of age when he was born. Photo by the Holstein-Fresian 
World. 



purposes. An unusually large percent- 
age of the Superior Class were born 
before their dams were two and one- 
half years of age and must have been 
first calves. The sires of a large per- 
centage of the Superior Class were also 
under two and one-half years when the 
dams were bred. On the other hand, 
just as large a percentage of the 
Superior Class as of the Inferior Class 
is from very old parents. 



AGE WHEN THE BEST RECORDS ARE 
MADE 

Table IV was arranged for the Supe- 
rior Class only. The best record was 
used in every case. If any of the cows 
herein considered have made a better 
record since the collection of this 
data this fact introduces an error. 
It is recognized that only a very few 
cows have ever made more than one 



Table IV. The Average Age of All the Superior Cows at the Time Their 
Records Were Made 





Group I 


Group II 


Group III 


Superior Class 


Number of Cows 

Average Age in Months. . 


86 
69.7 


121 
72.1 


404 
73.7 


611 

72.2 



176 



The Journal of Heredity 



limit of their possibilities for high 
production at about this age. This 
contention is supported from other 
sources/ although one investigator, - 
who attacked the problem* in an 
entirely difTerent manner, maintains 
that the highest production is not 
reached until much later in life. 

SUMMARY 

The parentage of superior or high 
producing dairy cows is no older than 
the parentage of comparatively inferior 
or low producing cows and thus the old 
animal is no more valuable as a parent 
than the young animal. 

As far as the age of either parent is 
concerned, the young born at one time 
in life seem to be just as valuable as 
the young born at any other time. 

A very large percentage of our cows 
are born of immature parents but the 
proven animal at any age is much more 
valuable for breeding purposes. 

On the average, cows make their 
best records at about six years of age. 

1 Pearl Raymond, The Change of Milk Flow with Age. Maine Agricultural Experiment 
Station Bulletin, No. 262. 1917. 

^ GowAN, J. W., Studies in Milk Secretion VIII. Maine Agricultural Expiriment Station 
Bulletin, No. 293. 1920. 



record above thirty pounds of butter 
in a week and most of those that 
have done so are here considered. This 
error, then, is in all probability very 
small. 

The group averages and the class 
average all show that the best records 
of the animals herein considered were 
made at an average age of about six 
years. Of course many were much 
older than this and many were younger, 
but it is well known that animals vary 
greatly in rapidity of development. 
It would seem that the numbers con- 
sidered are large enough to make the 
average significant even though it is 
recognized that most cows do not have 
a chance to make a record every year. 
The cow is most likely to be tested at 
the time she shows greatest promise. 
Since these high producers made their 
best records at six years of age, it 
seems only fair to assume that they 
were at the height of their productive 
capacity at this time. It would also 
indicate that cows generally reach the 



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